Figure 2: Zonal wind component (m s−1) at 600 hPa plotted over a three-day period as a function of longitude for the most representative (see Table 1) TCP system (a) and the most representative NTCP system (b). The zonal winds have been averaged over a latitude range from 10° N to 20° N. The darker red colors indicate larger easterly wind speeds, and darker blue colors indicate weaker easterlies. The black dashed line indicates the longitude of NPOL.